Manual de servicio SRPT 30 and SRPT 40A RPU Transmitters Manual

MARTIELECTRONICSRPU TRANSMITTER

MODELS: SRPT-30 SRPT-40A

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RF EXPOSURE WARNINGThis remote pickup unit (RPU) contains a radio frequency (RF) transmitter. During normal operation it sendsout radio frequency (RF) signals. In August 1996, the Federal Communications Commission (FCC) adoptedRF exposure guidelines with safety levels for wireless devices.

CAUTION: To maintain compliance with the FCCs RF exposure guidelines, the antenna(s) used for thistransmitter must be installed to provide a separation distance of at least 6 meters from all persons during normaloperation and must not be co-located or operating in conjunction with any other antenna or transmitter. Inaddition, no antenna with a gain of greater than 11 dBi shall be used.

Unauthorized antennas, modifications, or attachments could damage the transmitter and may violate FCCregulations.

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W A R N I N GTHIS EQUIPMENT MUST BE OPERATED WITH A 3-PRONGGROUNDED OUTLET RECEPTACLE. FAILURE TO USE A

PROPERLY GROUNDED OUTLET MAY RESULT IN IMPROPEROPERATION OR SAFETY HAZARD!

LIMITED WARRANTYThe Seller warrants that, at the time of shipment, the products manufactured by the Seller are free from defects inmaterial and workmanship. The Seller's obligation under this warranty is limited to replacement or repair of suchproducts which are returned to Marti at its factory, transportation prepaid and properly insured, provided:

a. Notice of the claimed defect is given to Marti within one (1) year [two (2) years for STL systems] from date oforiginal shipment and goods are returned in accordance with Marti instructions.

b. Equipment, accessories, tubes and batteries not manufactured by Marti are subject to only such adjustments asMarti may obtain from the supplier thereof.

c. This warranty does not apply to equipment which has been altered, improperly handled, or damaged in any way.The Seller is in no event liable for consequential damages, installation cost or other costs of any nature as a result of theuse of the products manufactured or supplied by the Seller, whether used in accordance with instructions or not.This warranty is in lieu of all others, either expressed or implied. No representative is authorized to assume for the Sellerany other liability in connection with Seller's products.

MAILING & SHIPPING ADDRESS:Broadcast Electronics

MARTI Electronics Division4100 North 24th Street

Quincy, IL 62301The United States of America

COPYRIGHT NOTICE2001 All Rights Reserved

Marti Electronics3rd printing, January 2003

No part of this manual may be reproduced, transmitted, transcribed, stored in a retrieval system , or translated into anylanguage, natural or computer, in any form or by any means, without the prior written permission of Marti Electronics.

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Artwork depicting circuitry in this manual is protected by copyright laws.

Information in this manual is subject to change without notice and does not represent a commitment on the part of MartiElectronics.

Marti Electronics may make improvements and/or changes in this manual or in the product described herein at any time.

This product could include technical inaccuracies or typographical errors.

PHONE NUMBERS:

Sales (817) 735-8134Service (217) 224-9600FAX (817) 735-9340

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ABOUT THIS MANUALThis manual supports both the SRPT-30 and SRPT-40A RPU transmitters for all standard (and some non-standard) frequency bands. The SRPT-30/40A in some frequency bands may not yet be available during theprinting of this manual. The manual will be revised as new frequency bands become available.

Manual Part Numbers:Kit, Binder and Manual: 979-9967-1Manual Only: 566-035-1

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TABLE OF CONTENTSIntroduction ........................................................................................................... 1

Specifications & Ordering................................................................................................. 4

Unpacking and Inspection ................................................................................................. 7

Installation ......................................................................................................................... 8

Antennas ........................................................................................................................... 16

Control, LED, & Connector Functions . 18

Operation ........................................................................................................................... 23

Theory of Operation .......................................................................................................... 31 Drawing 702-124 SRPT-30/40A Functional Block Diagram................................... 34 Drawing 702-117 SRPT-30/40A RF Systems & Control......................................... 35

Recommended Test Equipment 36

Tools For Alignment . 36

SRPT-30/40A Transmitter Factory Test Report ... 37

Calibration and Adjustments ................................................................. 38 Drawing 702-122 SRPT-30/40A Adjustment Locations.. 50

SRPT-30/40A Bill of Material and Schematics ............................................ 51

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INTRODUCTIONSee the SPECIFICATIONS & ORDERING section for a listing of available frequencyranges and power models.

SRPT-30 DUAL-CHANNEL RPU TRANSMITTER

SRPT-40A FREQUENCY AGILE RPU TRANSMITTER

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The Marti Models SRPT-30/40A are wide-band high power RPU Transmitters designed to operate in the RemotePick-Up Broadcast Service as defined in Part 74, Subpart D, of the FCC Rules and Regulations. The SRPT-30 replacesthe Marti RPT-30 series of RPUs. Like its predecessor, the SRPT-30 has two frequency channels and a four-inputmixer for mic/line audio. Unlike the RPT-30, the SRPT-30 uses synthesizer technology (not to be confused withfrequency agile) instead of the discrete crystal technology. Also the SRPT-30 is equipped with a wide-band poweramplifier that has a power output up to 30 watts that can be adjusted from the front panel. This, combined with the wide-band synthesizer, benefits the operator in the following ways: (1) Frequency separation between F1 and F2 frequencycan be up to 50 MHz and (2) No RF tuning required.

The SRPT-40A also uses synthesizer technology with a wide-band power amplifier and requires no tuning. It isfrequency agile up to 50 MHz with a front-panel adjustable output power up to 60 watts in some models. The frequencycan be dialed in from the front panel and will automatically tune precisely to all frequencies divisible by 5 KHz or6.25 KHz increments. It will also tune to within .00015% tolerance of most other frequencies not divisible by 5 KHz or6.25 KHz increments. Finally, the user may operate the SRPT-40A in channel mode where he may store and recall up to10 frequencies.

Refer to the SPECIFICATIONS & ORDERING section for a listing of available frequency ranges and powermodels. These transmitters, when used with their recommended companion receiver, provide a remote broadcast linkhaving audio quality not approached by conventional voice communication radio equipment. The SRPT-30/40Atransmitters operate from 110-120 VAC or 220-240 VAC (manually switched internally), 50/60 Hz. The transmitterscan also operate on 12-15 VDC or 15-30 VDC battery (or external supply) in fixed, portable, or mobile, service. Fouraudio input channels are provided with individual mixing gain controls. A meter and selector switch are provided formonitoring forward and reverse power, power supply voltage, PA current and audio compression.

SRPT-30/40A Features: Four balanced microphone mixing inputs, one switchable to balanced line level No RF tuning required Switching Power Supply operates on any AC voltage from 110-120 VAC or 220-240 VAC

(manually switched internally), 50/60 Hz LEDs indicate High VSWR, Over-Temperature, AFC Lock, and Transmit Illuminated VU Meter for displaying Forward/Reverse Power, PA current, Power Supply

voltage, and Audio Compression Output power adjustable from front panel External 12-15 VDC or 15-30 VDC supply capability and external transmit control When operating on external 12-15 VDC supply, RPU will still remained locked for

external supply voltages as low as 7 VDC (Max power will de-rate linearly below 12 VDC) Fully suppresses external voltage supply noise such as car alternator High speed imbedded -controller to perform the following additional features:

Power held constant over frequency, temperature, and voltage change High PA temp and VSWR warning indicators Auto frequency re-lock due to power outage Auto fold-back and recover due to high VSWR Auto shutdown due to very high PA temp auto recover after cool down Auto shutdown due to open/short-output auto recover

Can operate as TSL (Models SRPT30-450T and SRPT40A-450T)

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SRPT-40A Only Features: Continuous-duty output - 60 watts maximum in some models Frequency agile pushwheel switches allow selection of almost any frequency (100 Hz

steps) in operating band up to 50 MHz 10 user programmable channels No frequency look-up table required Remembers and locks-on last frequency during power-up Frequency resolution: 5 or 6.25 KHz steps .00004% accuracy

- Most other frequencies (100 Hz steps) - .00015% accuracy

SRPT-30 Only Features: Continuous-duty output - 30 watts maximum most models Two frequency channels, F1 and F2, selected at time of order Up to 50 MHz separation between frequency channels Selected frequencies divisible by 5 or 6.25 KHz steps have a .00004% accuracy

- Most other selected frequencies have a .00015% accuracy

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Models SRPT-30 and SRPT-40ARemote Pick-Up Broadcast TransmittersSPECIFICATIONS & ORDERINGConditions (unless specified otherwise): 1.5 VSWR, 110 VAC input with B+ = 13 Volts, 25C ambient

Frequency Bands andMaximum Output Power:

See ORDERING INFORMATION below.

Frequency Agility andAccuracy

SRPT-40A (450 models andless)

An executed dialed-in frequency that operates within model frequencyrange will have an accuracy within:(1) .00004% for frequency divisible by 5 or 6.25 KHz, or(2) .00015% for MOST frequencies NOT divisible by 5 or 6.25 KHz*

Frequency Agility andAccuracy

SRPT-40A (800 models andgreater)

An executed dialed-in frequency that operates within model frequencyrange will have an accuracy within:(1) .00004% for frequency divisible by 10 or 12.5 KHz, or(2) .00015% for MOST frequencies NOT divisible by 10 or12.5 KHz*

Frequency Selection andAccuracy

SRPT-30 (450 models and less)

Two frequencies only, F1 and F2, determined at time of order, mustoperate within model frequency range and will have an accuracy within:(1) .00004% for frequency divisible by 5 or 6.25 KHz, or(2) .00015% for MOST frequencies NOT divisible by 5 or 6.25 KHz*

Frequency Selection andAccuracy

SRPT-30 (800 models andgreater)

Two frequencies only, F1 and F2, determined at time of order, mustoperate within model frequency range and will have an accuracy within:(1) .00004% for frequency divisible by 10 or 12.5 KHz, or(2) .00015% for MOST frequencies NOT divisible by 10 or12.5 KHz*

Operating Temp. Range: -10C to +45CFrequency Stability (over

operating temperature range):0.0001%

Deviation: Adjustable, 20 KHz maxAudio Bandwidth: Standard: 7.5 KHz

Available: 5 KHz, 10 KHz, specials upon requestSignal-to-Noise: 53 dB, 5 KHz deviation, 75 sec pre/de-emphasis

Frequency Response: 1.5 dB from 50 Hz to Audio Bandwidth, 75 sec pre/de-emphasisDistortion: 2% from 50 Hz to Audio Bandwidth, 75 sec pre/de-emphasis

Spurious Emissions: More than 60 dB below carrierRF Connector: Type N-Female

RF Output Impedance: 50 OhmsAudio Inputs: Four balanced microphone (150 ohms) inputs (XLR-3) with mixing

controls. One input switchable to balanced line level at microphone #4input and D connector on rear panel.

Audio Input Levels: Microphone: -68 to -35 dBmLine: 0 to +10 dBm, 6-800 Ohms

Modulation Control: Broadcast-quality compressor/limiter built in.Encoding: Sub audible 27 Hz. tone encoder built in.

Metering/Indicators: Illuminated meter indicates forward and reverse power, PA current, B+,and audio compression. LEDs indicate TRANSMIT, AFC LOCK,HIGH VSWR, and HIGH TEMP.

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Controls: (4) Input level controls, METER control knob, ENCODE switch,POWER ADJUST pot, TRANSMIT switch, and MONITOR jack.SRPT-40A: FREQUENCY SELECT switches and EXECUTE switchSRPT-30: F1/F2 switch

Power Requirements: 110-120 VAC or 220-240 VAC (manually switched internally on powersupply for proper input), 50/60 HzExternal DC operation on 12 - 15 volts or 15 - 30 volts.

Approximate PA CurrentRating (at maximum power

output):

SRPT-40A: 8.5 to 10.5 AmpsSRPT-30: 6.5 to 7.5 Amps(The data above varies across frequency band and from model to model)

Accessory Connector: 15-pin D connector for DC power, remote control, encode, line levelinput.

Weight: Net: 8.25 Lbs (3.74 Kg).Packed: 16.75 Lbs (7.60 Kg).

Dimensions: 11.5in (29.21cm) W x 3.5in (8.89cm) H x 14.3in (36.83cm) D.Packed: 19in (48.26cm) W x 22in (55.88cm) H x 9in (22.86cm) D.

* - There does exist a few non-standard frequencies that will not automatically tune to within .00015% ofrequested frequency. For those frequencies, the operator must change to the nearest standard frequency andthen manually tune the reference oscillator to desired frequency. Consult factory for frequencies not perfectlydivisible by 5 KHz or 6.25 KHz. We will be able to tell you how close the output will come to desired frequency.

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ORDERING INFORMATIONConditions (unless specified otherwise): 1.5 VSWR, 110 VAC input with B+ = 13 Volts, 25C ambientMARTIPART #

FrequencyRange(MHz)

MaximumRF OutputPower (W)

Typical MAX RFOutput Power over

Frequency

Certifications

SRPT30-150 135-185 30 20W 135-140 MHz30W 140-180 MHz20W 180-185 MHz

FCC ID: DDE-RPU-60W-150S(FCC Part 74 Subpart D)

Emission Designators:25K0F3E, 30K0F3E

SRPT30-230 215-250 30 30W 215-250 MHzSRPT30-250 235-265 30 25W 235-245 MHz

30W 245-265 MHzSRPT30-330 300-350 30 20W 300-315 MHz

30W 315-350 MHzSRPT30-450-or-SRPT30-450T(for TSL RPU)

430-480 30 30W 430-480 MHz FCC ID: DDE-RPU-50W-450S(FCC Part 74 Subpart D)

Emission Designators:10K0F3E, 25K0F3E, 50K0F3E

SRPT30-950 935-965 20 20W 935-960 MHz18W 960-965 MHz

SRPT40A-150 135-185 60 50W 135-140 MHz60W 140-175 MHz50W 175-180 MHz40W 180-185 MHz


Emission Designators:25K0F3E, 30K0F3E

SRPT40A-230 215-250 30 30W 215-250 MHzSRPT40A-250 235-265 30 25W 235-245 MHz

30W 245-265 MHzSRPT40A-330 300-350 30 20W 300-315 MHz

30W 315-350 MHzSRPT40A-450-or-SRPT40A-450T(for TSL RPU)

430-480 50 50W 430-465 MHz45W 465-480 MHz


Emission Designators:10K0F3E, 25K0F3E, 50K0F3E

SRPT40A-950 935-965 20 20W 935-960 MHz18W 960-965 MHz

Available OPTIONS for the SRPT-30/40A TransmittersMarti No. Description585-141 12-15 VDC External Supply Cable585-142 15-30 VDC External Supply Cable585-139 12-15 VDC Mobile Repeat Cable, CR/AR-10 to SRPT-30/40A585-140 15-30 VDC Mobile Repeat Cable, CR/AR-10 to SRPT-30/40A585-143 Fixed Repeat Cable, CR/AR-10 to SRPT-30/40A700-250-13 Rack mounting kit700-252-2 Mobile mounting kit565-006-1 Racom 1402 Automatic Morse Code Station Identifier with mounting kit585-088 SRPT30/40A TSL to Racom Cable Assembly

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UNPACKING & INSPECTINGThis equipment was factory tested, inspected, packed, and delivered to the carrier with utmost

care. Do not accept shipment from carrier which shows damage or shortage until the carrier's agentendorses a statement of the irregularity on the face of the carrier's receipt. Without documentaryevidence, a claim cannot be filed.

Unpack equipment immediately upon receipt and thoroughly inspect for concealed damage. Ifdamage is discovered, stop further unpacking and request immediate inspection by local agent ofcarrier. A written report of the agent's findings, with his signature is necessary to support claim.Check your shipment against the shipping papers for possible shortage. Do not discard any packingmaterial until all items are accounted for. Small items are often thrown away with packing material.Packing material should be retained until equipment testing is completed. Any equipment returned tothe factory should be packed in original cartons, insured, and pre-paid.

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INSTALLATION Install rack-mounted equipment in a well-ventilated, well-grounded, and shielded rack cabinet.Do not locate solid-state equipment in a rack above tube-type equipment, which produces hightemperatures. It is highly recommended that if the equipment is mounted in a rack cabinet, a blowershould be installed in the cabinet as well. Problems can also be avoided by locating this unit away from other equipment which hastransformers that produce strong magnetic fields. These fields can induce hum and noise into theMarti equipment thus reducing performance. Strong radio-frequency (RF) fields should be avoidedwhere possible. Extensive shielding and filtering have been incorporated into this equipment to permitoperation in moderate RF environments. All equipment racks, cabinets, etc., should be bondedtogether by wide copper grounding strap to ensure that all system elements are at RF ground poten-tial.

Stationary Remote Broadcast InstallationThe basic stationary remote installation consists of the SRPT-30/40A transmitter, a 110-120 or 220-240 VAC

power source, microphones and other audio program sources, and a portable antenna. Remotes using portable antennasinside buildings have very limited range (typically less than one mile). If greater range is needed, consider locating thetransmitting antenna outside the building at a height necessary to provide a line-of-sight path to the receiving antenna.This may not be practical if a great length of coaxial cable is required. Many broadcasters are using the Marti mobilerelay system to do remotes from inside buildings. This system consists of the originating transmitter with its antennainside the building which transmits to a mobile relay parked outside the building. The mobile relay consists of a MartiModel AR-10 receiver and Marti RPT series transmitter with mobile antennas installed in a vehicle. The AR-10receiver picks up the encoded signal originating from the RPT series transmitter located inside the building,automatically turns on the relay transmitter (on a different frequency), which re-transmits the program to the distantreceiving antenna at the radio station studio or transmitter site. (Mobile relay equipment packages are available fromMarti.)

Stationary Remote Installation Procedure1. The transmitter is normally located near the announcer or engineer to permit access to gain controls, microphone

inputs, the monitor jack, and metering.

Personnel must not be near the antenna when radiating. Locate antenna as far as possible frompeople and equipment susceptible to RF radiation. Do not mount antenna directly on transmitter.Refer to ANSI C95.1 Limits on Non-Ionizing Radiation.

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2. With the SRPT-30/40A TRANSMIT/STANDBY switch in STANDBY position, plug the transmitter into agrounded, three-prong, 110-120 or 220-240 VAC outlet.

WARNING

THE MANUAL SWITCH ON THE INTERNAL SWITCHING POWER SUPPLY IS SET AT THEFACTORY TO THE 115 POSITION IF THE ORDER WAS FOR 110-120 VAC.

THE MANUAL SWITCH ON THE INTERNAL SWITCHING POWER SUPPLY IS SET AT THEFACTORY TO THE 230 POSITION IF THE ORDER WAS FOR 220-240 VAC.

IF THE OPERATOR PLANS TO OPERATE THIS UNIT AT AN AC VOLTAGE DIFFERENT THANWHAT IS STATED ON ORDER, IT IS THE REPONSIBILITY OF THE PURCHASER TO SWITCH TO

THE APPROPRIATE POWER SUPPLY POSITION.

WARNING

DO NOT PLUG INTO AC WITHOUT FIRST KNOWING THE POSITION OF THE AC INPUT SWITCHLOCATED ON THE SIDE OF THE INTERNAL POWER SUPPLY.

SEE AC LINE INPUT SELECTION 110-120 VAC OR 220-240 VAC SUB-SECTION IN THECALIBRATION AND ADJUSTMENTS SECTION FOR VERIFICATION AND CHANGING.

WARNING

THIS EQUIPMENT MUST BE OPERATED WITH A 3-PRONG, GROUNDED, 110-120 OR 220-240VOLT AC OUTLET RECEPTACLE!

FAILURE TO USE A PROPERLY GROUNDED OUTLET COULD RESULT IN A SAFETY HAZARDOR FAULTY EQUIPMENT PERFORMANCE.

IF AN EXTENSION CORD IS USED, IT MUST BE THE THREE-WIRE GROUNDING TYPE TOINSURE SAFETY.

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WARNING

DO NOT CUT OFF THE GROUND PIN OF A 3-PRONG PLUG!

EXCESSIVELY LONG EXTENSION CORDS SHOULD BE AVOIDED SINCE THE VOLTAGE DROPCAN DEGRADE EQUIPMENT PERFORMANCE.

DO NOT ALLOW THE SRPT-30/40A TO GET WET.

DO NOT OPERATE WHERE PERSONNEL TOUCHING THE TRANSMITTER (OR ITSMICROPHONE, ANTENNA, OR OTHER CONNECTED EQUIPMENT) ARE STANDING ON WET

GROUND OR CONCRETE.

3. For locations where AC power is not available, the SRPT-30/40A can be powered from a fully charged automobilebattery.

4. Connect a portable antenna such as the Marti PAV/150, PAV-450, or YC-450 to the ANTENNA connector on theback of the transmitter.

Mobile InstallationThe SRPT-30/40A transmitter can be installed in the vehicle where the TRANSMIT/STANDBY function can be

operated directly, or the transmitter can be located elsewhere (in the trunk of a car or rear of a van) and controlledremotely. The choice depends upon the type of vehicle and the type of operation anticipated. The antenna(s) are usuallymounted on top of the vehicle to provide maximum height.

Transmitter Mounting1. Locate transmitter where vent holes on top and rear of unit are not obstructed. Leave enough space for the mic. Plug

on the front panel and the accessory plug on rear of unit.

2. Hook the four mounting fasteners (in retracted position in the four slots on the sides of the transmitter. See Fig. 1.(Fasteners are in Mobile Mounting Kit, 700-252-2).

3. Mark the location of the two mounting holes in each fastener bracket. Drill 7/64 diameter holes into the mountingsurface at the marked places for #6 x 1/2 sheet metal screws.

4. Attach the mounting fasteners with the sheet metal screws provided. Secure the transmitter with the fasteners.

Receiver MountingFor mobile repeat using the Marti AR-10 Mobile Repeat Receiver, mount the receiver near the transmitter using the

three fasteners supplied in Mobile Mounting Kit, 700-252-2.

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SRPT-30/40A

700-252-2 MOBILE MOUNT FASTENERS

Mobile Remote ControlRemote control of the SRPT-30/40A transmitter requires a switch to control primary 12-15 VDC power (or 15-30

VDC) and a second switch to control the transmit function. The primary 12-15 VDC (or 15-30 VDC) controlrequirement can be met by tapping the ignition switch circuitry of the vehicle. The transmit function can be performedby installing a switch on the vehicle.

FIG. 2A and 2B show the electrical circuit of a mobile installation for 12-15 VDC (585-141) and 15-30 VDC (585-142), respectively.

Mobile RepeatMobile repeat operation is covered under STATIONARY REMOTE BROADCAST INSTALLATION.

Electrical connection for a 12-15 Volt supply is made through Mobile Repeat Cable No. 585-139. This cable isconnected between the SRPT-30/40A transmitter and AR/CR-10 receiver. Power is obtained by connecting the fusedRED wire to the 12-15 VDC battery or supply. The supply must be capable of delivering 10 Amps minimum. Theelectrical diagram of this cable is shown in FIG. 3A.

NOTICE

WHEN OPERATING THROUGH A CIGARETTE LIGHTER, THERE MAY BE A ONE TO TWO VOLTDROP DUE TO THE LENGTH OF INTERNAL VEHICLE WIRING AND THE LARGE AMOUNT OF

CURRENT REQUIRED TO OPERATE THE SRPT-30/40A AT HIGHER OUTPUT POWERS.

THE SRPT-30/40A WILL OPERATE WITH AN EXTERNAL INPUT VOLTAGE AS LOW AS 7 VDC.HOWEVER THE MAXIMUM RF OUTPUT POWER WILL DE-RATE LINEARLY AS THE EXTERNAL

INPUT VOLTAGE DROPS BELOW 12 VDC.

Electrical connection for a 15-30 Volt supply is made through Mobile Repeat Cable No. 585-140. This cable isconnected between the SRPT-30/40A transmitter and AR/CR-10 receiver. Power is obtained by connecting the fusedBLUE wire to the vehicle 15-30 VDC battery or supply. The supply must be capable of delivering 10 Amps minimum.The electrical diagram of this cable is shown in FIG. 3B.

Automatic Morse Code Station IdentifiersThe SRPT30/40A-450T TSL RPUs are used for sending data back from a transmitter site to the studio (also known

as telemetry). In older FCC requirements, un-manned transmitters required an automatic remote control system to senddata back to the studio for verifying that the transmitter was operating properly. Many broadcasters today are still using

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this system. Along with the data, a station identifier in morse code can also be input into the TSL. Marti typically usesthe RACOM MODEL 1402 Automatic Morse Code Station Identifier to accomplish this task. Marti stocks and sells theRACOM 1402 (part number 565-006-1) along with the interconnecting cable (part number 585-088). Typically, thecable is connected to the RACOM 1402 at the Marti facility. The customer can also connect up the cable as well. Referto Drawing 702-125.

Mobile Antenna InstallationOne or more mobile antennas are required depending upon the various receive and transmit frequencies and whether

antenna duplexing is used. Antennas are specified in the various system packages listed in the Marti literature. Theinstaller should follow the instructions supplied with the mobile antennas.

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Fixed Base Station and Repeater Installation

1. Install transmitter in standard rack by using Rack Mounting Kit No. 700-250-13 available from Marti.

CAUTION

ALLOW ONE PANEL SPACE ABOVE AND BELOW TRANSMITTER FOR INLET AIR-FLOW TOINTERNAL FAN.

2. Connect transmitting antenna to ANTENNA connector on SRPT-30/40A rear panel.

3. Plug transmitter into a 3-prong, grounded 110-120 or 220-240 VAC outlet.

WARNING


4. For fixed automatic repeater operation, connect Cable No. 585-143 (FIG. 4.) between accessory connectors of thereceiver and SRPT-30/40A transmitter. Connect receiving antenna to receiver J6 and transmit antenna to SRPT-30/40A ANTENNA connector.

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ANTENNASBASE STATION ANTENNA INSTALLATION CHECKLIST

The following suggestions are offered to help those responsible for antenna installations avoidcostly errors in assembly and adjustment. Marti Electronics assumes no responsibility for theinstallation and performance of antenna systems associated with its equipment. The followingsuggestions are not intended to be a complete step-by-step procedure, simply a listing of some of themost frequently reported errors in antenna system installation.

Antenna AssemblyFollow the manufacturer's instructions carefully. If no instructions were included with the antenna, call or write the

antenna manufacturer for instructions. Antennas which have phasing or stacking cables must be assembled carefully toavoid phase reversal or signal cancellation.

Transmission Line Connector AssemblyDo not use RG-58 U or RG-8 U cable for STL station antennas! They have too much loss at VHF and UHF

frequencies. Follow the instructions furnished by the manufacturer when cutting coaxial cable. Inspect the cable endsfor small metal fragments which can short-circuit the line inside the connector assembly. Check the line for a short-circuit condition after each connector is installed by using an ohmmeter. Pressurized line should be checked for severaldays under pressure before installation on a tower to ensure that there are no leaks in the line or fittings.

Moisture Proofing Coax Connectors and FittingsExtreme care must be exercised with coaxial cable before and after connectors have been installed to ensure that

moisture does not enter the line. Foam dielectric line can take on moisture absorption which is difficult to detect andremedy. Therefore, keep the line dry while in storage with ends tightly capped. Coaxial splices, connectors, and fittings,to be located outside should be made mechanically tight, then coated with a weather-proofing material over at least twolayers of vinyl plastic electrical tape. Moisture problems in antenna systems are usually traced back to connectors whichhave NOT been properly taped. The Marti K-1 Grounding and Weatherproofing Kit is recommended for use in eachnew antenna installation.

Location and Grounding of Coaxial CableKeep the RPU receiver coaxial cable as far from the broadcast transmitter and its coaxial cable as possible.

WARNING

DO NOT STRAP RECEIVER CABLE TO THE MAIN ANTENNA CABLE AT ANY POINT.

PLACE THE RECEIVER ANTENNA COAXIAL CABLE ON THE OPPOSITE SIDE OF THE TOWERFROM THE MAIN ANTENNA CABLE.

Maintain maximum separation between these cables at all points, including the distance from tower base to transmitterbuilding as well as inside the building.

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System GroundingIt is essential that the RPU antenna system be properly grounded for safety and proper operation.

Antenna Installation and AdjustmentThe polarization of the transmit and receive antennas of the RPU system must be the same! This means that if the

transmitting antenna is vertical, the receiving antenna must also be vertical. Each antenna should be attached to thetower using the proper side mount or top mount hardware. If an RF wattmeter is available, each antenna andtransmission line can be checked for VSWR when the transmitter is supplying power to it. The VSWR should be lessthan 1.5 to 1 (1.5:1).

If the antenna system fails to give the predicted signal strength level, the followingitems should be checked:1. Check for correct assembly of antenna.2. Check that antennas have same polarity.3. Check VSWR of both transmit and receive antennas. VSWR should be less that 1.5:1.4. Check for obstructions in the path such as trees and man-made structures. The base antenna must be high enough to

provide a line-of-sight path to the remote transmitting antenna.

CAUTION & WARNING

YOU CAN BE KILLED IF AN ANTENNA COMES IN CONTACT WITH ELECTRIC POWER LINESOR EXPOSED ELECTRICAL WIRING.

FOR YOUR SAFETY, USE EXTREME CAUTION WHEN IN-STALLING ANTENNAS.

KEEP AWAY FROM POWER LINES.

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CONTROL, LED, & CONNECTORFUNCTIONSACCESSORY Input ConnectorAudio Input:

When Input 4 is switched to HI level, audio can be fed into pins 4 and 5 of the ACCESSORY connector on therear of the transmitter. Input level should be between 0.2 volts to 2.0 volts rms. The output impedance of the deviceconnected to Input 4 should be 8 - 600 ohms. For unbalanced operation ground pin 5 to pin 1, 8, 11, or 12 and connectaudio to pin 4. Use standard 15-pin subminiature D female connector with cover.

Transmit Control:TRANSMIT control can be accomplished remotely by a switch circuit connected between pin 15 and one of the

available ground pins (pin 1, 8, 11, or 12).

External DC supply:The SRPT-30/40A can be powered externally by either a 12-15 Volt DC supply or a 15-30 Volt supply. If powered

off a 12-15 Volt supply, connect three positive leads of the supply to pins 6, 7, and 14. Connect three negative leads ofthe supply to three ground pins (pins 1, 11, and 12). Each of the three positive leads and each of the three negative leadsshould be an 18 gauge wire. You may also use one 12 gauge wire for each positive and negative leads and split thestranded ends into three at the connector end.

ATTENTION

FOR 12-15 VOLT EXTERNAL SUPPLY, THE OPTIMUM VOLTAGE IS FROM 12 TO 15 VOLTS.

APPLYING A VOLTAGE LOWER THAN 12 VOLTS, WILL LIMIT THE MAXIMUM RF OUTPUTPOWER.

ALSO, THE EXTERNAL BATTERY OR POWER SUPPLY SHOULD BE CAPABLE OF HANDLING ACONSTANT 10 AMPS. THERE WILL BE A DROP IN VOLTAGE ACROSS THE POWER CABLES.

THE POWER CABLES SHOULD BE AS SHORT AS POSSIBLE AND AS HEAVY GAUGE ASPOSSIBLE. EXPECT A COUPLE OF VOLTS DROP WHEN OPERATING THROUGH A CIGARETTE

LIGHTER.

If powered from a 15-30 Volt supply, connect three positive leads of the supply to three 15-30VDC pins (pins 2, 3,and 10). Connect three negative leads of the supply to three ground pins (pins 1, 11, and 12). Each of the three positiveleads and each of the three negative leads should be an 18 gauge wire. You may also use one 12 gauge wire for eachpositive and negative leads and split the stranded ends into three at the connector end.

ATTENTION

FOR 15-30 VOLT EXTERNAL SUPPLY, IF APPLYING A VOLTAGE LESS THAN 16 VDC, THESRPT-30/40A EXTERNAL B+ ADJUST POT ON THE TWO-STAGE RF POWER AMPLIFIER BOARD

SHOULD BE ADJUSTED TO ABOUT 12 VDC.

IF THIS IS THE CASE, THE MAXIMUM RF OUTPUT POWER COULD BE LIMITED.

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CAUTION & WARNING

NEVER INSTALL AND CONNECT THE 12-15 VOLT AND THE 15-30 VOLT SUPPLIES AT THESAME TIME.

ALSO, NEVER CONNECT THE 15-30 VOLT SUPPLY TO THE 12-15 VOLT PINS AND NEVERCONNECT THE 12-15 VOLT SUPPLY TO THE 15-30 VOLT PINS.

DOING SO MAY DAMAGE THE INTERNAL SWITCHING SUPPLY OR EITHER OF THEEXTERNAL DC SUPPLIES.

CAUTION & WARNING

NEVER CONNECT THE SRPT-30/40A TO THE AC LINE AND EITHER OF THE EXTERNAL DCSUPPLIES AT THE SAME TIME.

DOING SO MAY DAMAGE THE INTERNAL SWITCHING SUPPLY OR THE EXTERNAL DCSUPPLY.

AC LINE Switch, AC Receptacle & FuseWhen the transmitter is not in use or if the SRPT-30/40A is to run off of an external supply, the AC LINE switch

should be in the OFF position.

When ready to use the SRPT-30/40A off of the AC line voltage, plug power cord into the AC Receptacle and switchthe AC LINE switch to the ON position.

The AC line fuse is rated at 2.5 amps.

WARNING

DO NOT PLUG INTO AC WITHOUT FIRST KNOWING THE POSITION OF THE AC INPUT SWITCHLOCATED ON THE SIDE OF THE INTERNAL SWITCHING POWER SUPPLY.


AFC LOCK LEDThe AFC LOCK LED will either be flashing or solid green at all times, except during initial power up and in that

case it will only be off for a few seconds.

When the SYNTHESIZER is searching for a frequency to lock on to and is therefore not locked, the AFC LOCKLED will flash green. When the SYNTHESIZER finds and locks onto the frequency it was searching for, the AFCLOCK LED will stay on, solid green. Three seconds after the SYNTHESIZER becomes locked, it will then be ready andwill enable the transmitter to output power.

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In normal conditions, the SYNTHESIZER will not come unlocked unless sent a command to change to change toa new frequency. However, other conditions can cause the SYNTHESIZER to come unlocked such as an AC line surgeor a sudden and very large change in VSWR. In those cases, the SYNTHESIZER will re-lock back on the assignedfrequency. The AFC LOCK LED will flash green until the SYNTHESIZER is locked. Once the SYNTHESIZER islocked it will stay on, solid green.

ANTENNA ConnectorConnection of various antenna systems is covered under INSTALLATION and ANTENNAS. It is only necessary

for the operator or announcer to see that the ANTENNA connector is tight and that the antenna is clear of objects whichmay affect its radiation efficiency.

CAUTION & WARNING

THE ANTENNA CONNECTOR IS A TYPE N FEMALE CONNECTOR AND REQUIRES A MATINGTYPE N MALE CONNECTOR.

PLUGGING IN A UHF TYPE (PL-259 OR SO-239) INTO THE ANTENNA CONNECTOR WILLDAMAGE AND SHORT OUT THE ANTENNA CONNECTOR. THIS COULD BURN UP THE PA

MODULE AND OTHER INTERNAL COMPONENTS.

ENCODE SwitchThe internal subaudible encoder can be switched ON or OFF by the front panel switch. Encoding is used to

activate a repeater station, tape recorder, etc.

FREQUENCY SELECT Pushwheel Switches and EXECUTE Switch (SRPT-40A only)Dial in the numbers that represent a frequency, channel number, or other command using the FREQUENCY

SELECT Pushwheel switches. Then press and release the EXECUTE switch to send the command numbers on theFREQUENCY SELECT pushwheel switches to the internal controller to be decoded and executed. See theOPERATION section for a listing and understanding of all commands.

F1/F2 Switch (SRPT-30 only)Switching to the F1 position will cause the transmitter to lock onto the frequency that was configured at the factory

as F1. Switching to the F2 position will cause the transmitter to lock onto the frequency that was configured at thefactory as F2. The F1 and F2 frequencies are selected by the purchaser at the time of order.

AUDIO GAIN ControlsThe GAIN potentiometer located above each input connector provides an independent level adjustment for that

input. Each GAIN potentiometer is adjusted as follows:1. Connect input source at normal audio level.

2. Turn GAIN potentiometer to maximum counter-clockwise (OFF) position.

3. Place TRANSMIT/STANDBY switch in STANDBY position and allow METER pointer to reach 0 VU. Slowlyincrease gain (clockwise) until METER begins deflecting to the left on audio peaks. Maximum deflection should be-3 to -5 VU on the METER scale. This indicates 100% modulation of the transmitter. Excessive gain settings causehigh compression values which result in annoying increase in background noise. A 600 ohm headset may be

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plugged into the MONITOR jack to aid in arriving at the proper gain adjustment. In high noise environments, close-talk the microphone and reduce MIC gain until a maximum of -2 VU gain-reduction is indicated.

4. Once the proper gain level is determined, it will not be necessary to change it for that particular microphone or tapeplayer. The broadcast quality compressor/limited built into the unit will maintain modulation at the maximum levelwhile preventing over-modulation.

HIGH TEMP LEDWhen the internal controller detects a PA temperature between 85 and 100 degrees C, the HIGH TEMP LED will

flash red at a rate of once per second.

When the internal controller detects a PA temperature of greater than 100 degrees C, the RF output power willcompletely shutdown, and the HIGH TEMP LED will flash red at a rate of twice a second. The RF output power willstay shutdown until the PA temperature has dropped below 85 degrees C. When the internal controller detects that thePA temperature is below 85 degrees C, it will turn off the HIGH TEMP LED and then enable the PA to transmit power.

A HIGH TEMP alarm could be due to the fan malfunctioning, the SRPT-30/40A placed in a closed-in area withlimited air circulation, or an experience of high VSWR.

HIGH VSWR LEDWhen the internal controller detects a VSWR of greater than 2 but less than 4, the HIGH VSWR LED will flash red

at a rate of once per second.

When the internal controller detects a VSWR of greater than 4 but less than 6, the output power will limit to amaximum of half the rated power (that was set using the MAX PWR pot (R74) located on the synthesizer see TUNE-UP and ADJUSTMENTS section) and the HIGH VSWR LED will flash red at a rate of twice per second. When thedetected VSWR falls less than 4, the output will resume to its previous power setting, the HIGH VSWR LED will flashat a rate of once per second if VSWR greater than 2, and will turn off if VSWR is less than 2.

When the internal controller detects a VSWR of greater than 6, or detects a reverse power of greater that one-thirdthe maximum rated output power, the output power will immediately shut off, the TRANSMIT LED will flash red, andthe HIGH VSWR LED will flash rapidly. Every three seconds the controller will attempt to turn on the transmit outputbut will again shut down if the conditions have not changed. If this occurs, even if the operator turns off the TRANSMITswitch, the HIGH VSWR LED will still flash rapidly. The only way to stop the HIGH VSWR LED from flashing, is torepair the output (i.e., loose connection of output, wrong connector type, wrong cable, faulty antenna, short circuit cable,etc), and then turn the TRANSMIT switch on (if it was off), and after 3 seconds if the controller does not detect a veryhigh VSWR or high reverse power, the transmit output power will come on.

METER and METER SELECT KnobWhen the METER SELECT Knob is either in the FORWARD POWER or REVERSE POWER position, the

corresponding measurement can be read off of the top "WATTS" scale of the METER.

When the METER SELECT knob is either in the PA CURRENT or the B+ position, the correspondingmeasurement can be read off of the middle VOLTS/AMPS scale of the METER.

When the METER SELECT knob is in the AUDIO COMPRESSION position, the corresponding measurement canbe read off of the bottom VU scale of the METER.

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MIC Input ConnectorsThese balanced inputs are for a 150 ohm dynamic microphone such as the Shure BG 1.0 with standard XLR-3 or

A3M connector. Microphone connections are given in INSTALLATION.Input 4 can operate at MIC LEVEL or HIGH LEVEL by means of a SELECTOR switch inside the transmitter just

behind the Input 4 pot. The unit is factory selected for HI (HIGH) LEVEL balanced input for use with tape machines,etc. To convert Input 4 to MIC (microphone) LEVEL, remove top cover and move switch to MIC.

MONITOR JackThe MONITOR jack is active in STANDBY and TRANSMIT positions of the TRANSMIT/STANDBY

switch. A high-quality headset having 300 ohms or higher impedance can be plugged into the MONITOR jack to makeadjustments or to monitor the quality of the audio being transmitted. A miniature, single circuit, 1/8 inch, phone plugshould be used with the MONITOR jack.

POWER ADJUST PotWhen the SRPT-30/40A is transmitting, this pot can be adjusted to increase or decrease the output power from the

MAXIMUM power setting to almost zero Watts.

TRANSMIT LEDWhen the TRANSMIT/STANDBY switch is in the STANDBY position, the SRPT-30/40A will not transmit and

the TRANSMIT LED will be off.

When the TRANSMIT/STANDBY switch is in the TRANSMIT position but the SYNTHESIZER is not ready, theSRPT-30/40A will not transmit and the TRANSMIT LED will flash red.

When the TRANSMIT/STANDBY switch is in the TRANSMIT position and the SYNTHESIZER is ready (whichis always three seconds after the SYNTHESIZER becomes locked), the SRPT-30/40A will transmit and theTRANSMIT LED will be on, solid red.

TRANSMIT/STANDBY SwitchThis switch is placed in STANDBY position to shut off the output power. The synthesizer will still be locked on

frequency as indicated by the solid AFC LOCK LED. The TRANSMIT/STANDBY switch is placed in theTRANSMIT position when transmission is desired. The output power will turn on immediately at an output power thatcorrelates to the POWER ADJUST position. The TRANSMIT/STANDBY switch should be returned to theSTANDBY position as soon as a transmission is completed.

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OPERATIONConnect up SRPT-30/40A to the AC Line Receptacle or ExternalDC Supply

CAUTION & WARNING

NEVER CONNECT THE SRPT-30/40A TO THE AC LINE AND EITHER OF THE EXTERNAL DCSUPPLIES AT THE SAME TIME.

DOING SO MAY DAMAGE THE INTERNAL SWITCHING SUPPLY OR THE EXTERNAL DCSUPPLY.

AC Line OperationPosition AC LINE switch to OFF, then plug SRPT-30/40A into a 110-120 VAC (if internal supply switched to

115) or 220-240 VAC (if internal supply switched to 230), grounded, 3-prong receptacle.

WARNING

DO NOT PLUG INTO AC WITHOUT FIRST KNOWING THE POSITION OF THE AC INPUT SWITCHLOCATED ON THE SIDE OF THE INTERNAL POWER SUPPLY.


WARNING

THIS EQUIPMENT MUST BE OPERATED WITH A 3-PRONG, GROUNDED, 110-120 or 220-240 VACRECEPTACLE!


IF AN EXTENSION CORD IS USED, IT MUST BE THE THREE-WIRE GROUNDING TYPE TOINSURE SAFETY.

DO NOT CUT OFF THE GROUND PIN OF A 3-PRONG PLUG!!

External DC Supply (12-15 Volt) OperationMake sure that the SRPT-30/40A is not connected to an AC line. Place the front panel AC LINE switch in the ON

position. This turns off External DC Supply (12-15 Volt) to the unit.

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The external supply or battery must be capable of delivering 8/10 Amps if running the SRPT-30/40A at maximumoutput power. Connect up the unit using the Marti 585-141 12-15 VDC External Supply Cable. If choose to build yourown cable then follow the drawing on Figure 2A: Connect three positive leads of the supply to pins 6, 7, and 14 of a 15-pin female D connector. Connect three negative leads of the supply to three ground pins (pins 1, 11, and 12) of the 15-pin female D connector. Each of the three positive leads and each of the three negative leads should be an 18 gaugewire. You may also use one 12 gauge wire for each positive and negative leads and split the stranded ends into three atthe connector end.

ATTENTION

FOR 12-15 VOLT EXTERNAL SUPPLY, THE OPTIMUM VOLTAGE IS FROM 12 TO 15 VOLTS.

APPLYING A VOLTAGE LOWER THAN 12 VOLTS, WILL LIMIT THE MAXIMUM RF OUTPUTPOWER.

ALSO, THE EXTERNAL BATTERY OR POWER SUPPLY SHOULD BE CAPABLE OF HANDLING ACONSTANT 10 AMPS. THERE WILL BE A DROP IN VOLTAGE ACROSS THE POWER CABLES.

THE POWER CABLES SHOULD BE AS SHORT AS POSSIBLE AND AS HEAVY GAUGE ASPOSSIBLE. EXPECT A COUPLE OF VOLTS DROP WHEN OPERATING THROUGH A CIGARETTE

LIGHTER.

It is best to have an external switch between the external supply and the unit. Make sure the switch is in the openposition before connecting it to external supply. Otherwise make sure that when connecting the positive lead to theexternal source that the 15-pin D connector is not connected to the SRPT-30/40A.

With the front panel AC LINE switch in the ON position, plug in the 15-pin D connector into the ACCESSORYconnector located in the rear of the SRPT-30/40A. Turn on external supply (if have a switch). With a voltmeter, measurethe voltage on the output of the external supply insuring that it is between 12 and 15 VDC. Switch the front panel ACLINE switch to the OFF position. The unit should power up.

External DC Supply (15-30 Volt) OperationMake sure that the SRPT-30/40A is not connected to an AC line. The front panel AC LINE switch does not control

the External DC Supply (15-30 Volt) operation. Therefore it does not matter what position it is in.

The external supply or battery must be capable of delivering 8/10 Amps if running the SRPT-30/40A at maximumoutput power. Connect up the unit using the Marti 585-142 15-30 VDC External Supply Cable. If choose to build yourown cable then follow the drawing on Figure 2B: Connect three positive leads of the supply to three 15-30VDC pins(pins 2, 3, and 10). Connect three negative leads of the supply to three ground pins (pins 1, 11, and 2). Each of the threepositive leads and each of the three negative leads should be an 18 gauge wire. You may also use one 12 gauge wire foreach positive and negative leads and split the stranded ends into three at the connector end.

It is best to have an external switch between the external supply and the unit. Make sure the switch is in the openposition before connecting it to external supply. Otherwise make sure that when connecting the positive lead to theexternal source that the 15-pin D connector is not connected to the SRPT-30/40A.

Plug in the 15-pin D connector into the ACCESSORY connector located in the rear of the SRPT-30/40A. Turn onexternal supply (if have a switch). With a voltmeter, measure the voltage on the output of the external supply insuringthat it is between 12 and 15 VDC. The unit should power up.

From 16 to 20 VDC, the SRPT-30/40A will transmit up to 50 Watts RF output. From 20 to 30 VDC the SRPT-40Amaximum output power will derate linearly down to 20 watts.

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CAUTION & WARNING

NEVER INSTALL AND CONNECT THE 12-15 VOLT AND THE 15-30 VOLT SUPPLIES AT THE SAME TIME.

ALSO, NEVER CONNECT THE 15-30 VOLT SUPPLY TO THE 12-15 VOLT PINS AND NEVER CONNECT THE12-15 VOLT SUPPLY TO THE 15-30 VOLT PINS.

DOING SO MAY DAMAGE THE INTERNAL SWITCHING SUPPLY OR EITHER OF THE EXTERNAL DCSUPPLIES.

Connect up AntennaConnect antenna to the ANTENNA connector on the SRPT-30/40A rear panel. Connection of various antenna

systems is covered under INSTALLATION and ANTENNAS.

CAUTION & WARNING

THE ANTENNA CONNECTOR IS A TYPE N FEMALE CONNECTOR AND REQUIRES A MATINGTYPE N MALE CONNECTOR.

PLUGGING IN A UHF TYPE (PL-259 OR SO-239) INTO THE ANTENNA CONNECTOR WILLDAMAGE AND SHORT OUT THE ANTENNA CONNECTOR. THIS COULD BURN UP THE PA

MODULE AND OTHER INTERNAL COMPONENTS.

CAUTION

DO NOT TURN ON AC LINE OR EXTERNAL DC POWER UNTIL ANTENNA HAS BEENPROPERLY CONNECTED TO ANTENNA CONNECTOR!

Power-Up SRPT-30/40AIf using AC line, turn on SRPT-30/40A by turning on front panel AC LINE switch. If using 12-15 Volt or 15-30

Volt external DC supply, turn on SRPT-30/40A by turning on external DC supply. Refer to the External DC SupplyOperation procedure above for proper installation and operation.

The SRPT-30/40A will begin a power-up routine. The front panel meter will illuminate immediately. After aboutthree seconds the AFC LOCK LED will begin flashing green indicating that the synthesizer is searching for the lastfrequency it was last locked on to.

If the TRANSMIT/STANDBY switch is in the TRANSMIT position, the TRANSMIT LED will flash red in unisonwith the green flashing AFC LOCK LED. Once the synthesizer has found and locked onto the frequency, the AFCLOCK LED will immediately stay on solid green and the TRANSMIT LED will continue to flash red for threeadditional seconds. After the three seconds, the SYNTHESIZER will be ready, will enable the power amplifier totransmit RF power, and the TRANSMIT LED will stay on solid red.

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If the TRANSMIT/STANDBY switch is in the STANDBY position, the TRANSMIT LED and hence, thetransmitter RF power, will be off and will stay off even after the SYNTHESIZER has locked and the AFC LOCK LEDhas illuminated solid green. When the TRANSMIT/STANDBY switch is placed in the TRANSMIT position (and threeseconds have elapsed since the SYNTHESIZER became locked) the PA will immediately begin transmitting and theTRANSMIT LED will illuminate solid red.

Adjusting Output PowerTurn the METER CONTROL knob to the FORWARD POWER position and observe the forward power reading on

the top scale of the METER. Using a small flat-head screwdriver, adjust the POWER ADJUST pot (located about ofan inch behind the POWER ADJUST bezel ring) to adjust the forward power to a desired output power as indicated onthe METER.

What Frequency Will the SRPT-30/40A Power-Up on?SRPT-30 Only:

The SRPT-30 will power-up on frequency F1 or F2 depending on the position of the F1/F2 front panel switch. Thefrequencies corresponding to F1 and F2 were determined at the time of order and are hard coded within the synthesizer.

SRPT-40A Only:

The SRPT-40A will always power up on the last frequency it was locked onto before last power-down. If youre notsure what frequency the SRPT-40A will power up on, first make sure that the POWER ADJUST pot is at a minimum(turned fully counter-clockwise) before powering up the SRPT-40A. After the SYNTHESIZER is locked and theTRANSMIT/STANDBY switch is set in the TRANSMIT position, monitor the RF output with a frequency counter. Ifnecessary, increase the POWER ADJUST pot (turn clockwise) slowly until the frequency counter registers a frequencyreading.

WARNING

NEVER CONNECT THE FREQUENCY COUNTER DIRECTLY TO THE RF OUTPUT CONNECTOROF THE SRPT-30 OR SRPT-40A.

THE FREQUENCY COUNTER SHOULD BE COUPLED OFF OF AN RF COUPLER OR A WATTMETER.

EXCEEDING THE INPUT POWER RATING OF THE FREQUENCY COUNTER COULD DOINTERNAL DAMAGE TO IT.

Inputting AudioPlug in microphones (Inputs 1 - 3) or tape player (Input 4 internally switched to HI position; See MIC Input

Connections, above) and check operation by setting the METER CONTROL knob to the AUDIO COMPRESSIONposition and observing the compression on METER and by a headset plugged into MONITOR jack. Set AUDIO GAINcontrols paragraph in the CONTROL & CONNECTOR FUNCTIONS section for how to adjust for no more than -3 VUaudio compression on the METER.

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Changing Output Frequency DirectSRPT-30 Only:

Simply change the position of the F1/F2 front panel switch and the unit will change to the corresponding frequency.

SRPT-40A Only:To change the frequency of the SRPT-40A, the S1 dip-switches on the Front Panel Control & Meter board (800-

385A) behind the front panel (see the SRPT-40A Adjustment Locations) need to be set with switches 1 and 2 in theON position and switches 3 and 4 in the OFF position. These positions are the normal position and are set at thefactory, so there should be no need to remove the top cover.

When the S1 switches are set as described in the last paragraph, then all that is required is to enter the desiredfrequency from left to right into the FREQUENCY SELECT pushwheel switches and then press and release theEXECUTE pushbutton switch.

All seven digits on the front panel FREQUENCY SELECT pushwheel switches must be entered. The frequency isentered in MHz where the first three digits represent the left side of the decimal place, and the last four digits representthe right side of the decimal place. For example, the frequency 450.0125 MHz will simply be entered as 4500125.

If a valid frequency is entered and the EXECUTE pushbutton is pressed and released, then the RF output power willimmediately turn off (if it was on to begin with) and the SYNTHESIZER will go through its normal routine in searchingand locking onto the requested frequency. When the frequency is found, the AFC LOCK LED will stop flashing andilluminate solid green. After three seconds the TRANSMIT LED will stop flashing and illuminate solid red (assumingthe TRANSMIT/STANDBY switch is in the TRANSMIT position) and the SRPT-40A will resume transmitting at thenew frequency and at the same output power it was before leaving the previous frequency.

What is A Valid Output Frequency?A valid output frequency is defined as a frequency that operates within the model bandwidth and is either a standard

frequency, or is a non-standard frequency that falls within .00015% of the requested frequency. A standard outputfrequency is one that is divisible by 5 or 6.25 KHz for 450 band models and less, and divisible by 10 or 12.5 KHz forgreater than 450 band models. All other frequencies are considered non-standard frequencies. The SRPT-30/40A willlock on standard output frequencies within a .00004% tolerance. The SRPT-30/40A will lock on about 95% of non-standard frequencies. The tolerance of these frequencies fall within .00015% of the requested frequency. If thesynthesizer determines that the non-standard frequency will fall outside .00015% of the requested frequency, then thisis considered an invalid frequency and it will not change to the requested frequency.

SRPT-30 Only:There are only two frequencies to choose from, F1 and F2, as configured at the factory, and are always considered

valid. However, at the time of order, if the customer requires a frequency that is not divisible by 5 or 6.25 KHz (or by 10or 12.5 KHz for > than 450 MHz models), we can determine immediately whether or not the requested frequencies willfall within .00015% tolerance. If one or both frequencies do fall not within this tolerance, then the order will beconsidered special and must be determined by the engineering department at Broadcast Electronics if we can tune to therequired frequencies.

SRPT-40A Only:If an invalid frequency is entered in, or if the same frequency that the SRPT-40A is currently locked on to is entered

in, then the SRPT-40A will remain at its current frequency, i.e., nothing will happen. If the operator desires to change toa frequency that is invalid, he must choose the closest valid frequency and then manually tune the reference oscillator onthe synthesizer to get to desired frequency. However, if the operator tunes the reference oscillator to get to an invalidfrequency, then when needing to change to another frequency (valid or non-valid), the operator may have to retune thereference oscillator again.

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Changing Output Frequency via Channel Select SRPT-40AOnly

The frequency can also be changed by entering a channel number that was previously stored with a frequency. SeeStoring Output Frequencies into Channels for instructions on how to store frequencies. There are ten channelsavailable for storing and recalling frequencies. These ten channels are preset with default or customer requestedfrequencies at the factory.

To change frequency via channel select, the S1 dip-switches behind the front panel must be set with switches 1 and2 in the ON position and 3 and 4 in the OFF position. These are the default positions and are in the same position aswhen changing the frequency direct. So theres no need to remove the top cover.

Now youre ready to enter the channel. This is done by setting the six left-most digits (digits 2-7) of theFREQUENCY SELECT pushwheel switches equal to zero. Then the far right digit (digit 1) is set to the channel ofchoice (channel 0 channel 9). After entering the channel, press the EXECUTE pushbutton down and then release. TheSYNTHESIZER will change to the frequency that was stored in the channel.

WARNING

THE REMAINING OPERATIONS ARE FEATURES THAT REQUIRE SETTING INTERNAL DIP-SWITCHES.

IN ALL CASES, WHEN PERFORMING THESE OPERATIONS, THE SRPT-40A MUST BE ON ANDTHE TOP COVER MUST BE REMOVED.

WHEN THE OPERATION IS COMPLETE, ALWAYS SET THE INTERNAL S1 DIP-SWITCHES WITHSWITCHES 1 AND 2 ON AND SWITCHES 3 AND 4 OFF. THEN RE-INSTALL THE TOP COVER.

Storing Output Frequencies into Channels SRPT-40A OnlyThe SRPT-40A must be locked on a frequency before storing that frequency into one of the ten available channels.

It is not necessary, however, that the SRPT-40A be transmitting, hence the TRANSMIT/STANDBY switch can be inSTANDBY.

First, lock on to the desired frequency either directly or via channel select. Remove the top cover of the SRPT-40A.Set the S1 dip-switches (located behind the front panel) as follows: Switches 1, 3, and 4 set to the OFF position andswitch 2 set to the ON position.

Next, set the six left-most digits (digits 2-7) of the FREQUENCY SELECT pushwheel switches equal to zero. Thenthe far right digit (digit 1) is set to the channel of choice (channel 0 channel 9) to be stored. After entering the channel,press the EXECUTE pushbutton down and then release. The current frequency-in-lock will be stored in the selectedchannel and the SRPT-40A will remain at its current frequency. If you need to store more channels, repeat the steps inthis paragraph.

Finally, put the S1 dip-switches back to where they were, i.e., switches 1 and 2 in the ON position and switches 3and 4 in the OFF position. Re-install the top cover.

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It would be a good idea to test the stored channel(s) by changing the frequency to some other frequency and thenrecalling the stored channel(s).

Control Switch Settings SRPT-40A OnlyControl Switch Settings enable or disable important controls used in the SRPT-40A. These control settings include

the following:Power Adjust PotHiHi VSWR FoldbackReverse Power CalibrationForward Power CalibrationHiHi Temperature ShutdownDirect Frequency ChangeChannel Frequency Change

Refer to TABLE (1) - Control Switch Settings Command for disabling or enabling the desired controls. Removethe top cover. Set the internal dip-switch S1 switches and the FREQUENCY SELECT pushwheel decimals as outlinedin Table (1). The entries in BOLD are default settings from the factory

When all FREQUENCY SELECT pushwheel decimals have been set to their required values that correspond to thedesired control switch setting, you must send the command by pressing the EXECUTE pushbutton down and thenreleasing. The internal controller will enable or disable the control. Set the internal dip-switch S1 back to its normalposition with switch 1 and 2 ON and switch 3 and 4 OFF. Re-install top cover.

Following is a description of the control settings:

Power Adjust Pot The default for this setting is enabled which allows the user to change the power from almost0 Watts to the maximum RF output power setting via the front panel POWER ADJUST pot. Refer to the MaximumPower Setting paragraph in the CALIBRATION AND ADJUSTMENTS section of this manual for information onhow to set the maximum power. If this user disables this setting, then the RF output power will maintain where last setand tuning of the POWER ADJUST pot will have no effect.

HiHi VSWR Foldback The default for this setting is enabled. This means when a VSWR is detected greater than4, the power will limit to one-half the maximum power setting. If VSWR foldback is disabled, then the forward RFpower will not try to foldback, even when the controller detects a VSWR of greater than 4. The HIGH VSWR LED willstill flash however. For maintaining long life from the power amplifier, it is not recommended to disable VSWRFoldback.

Reverse Power Calibration The default setting for this setting is disabled. This setting should only be enabledduring calibration (see the Reverse Power Calibration paragraph in the CALIBRATION AND ADJUSTMENTSsection).

Forward Power Calibration The default setting for this setting is disabled. This setting should only beenabled during calibration (see the Forward Power Calibration paragraph in the CALIBRATION ANDADJUSTMENTS section).

HiHi Temperature Shutdown The default for this setting is enabled. See High Temp LED paragraph in theCONTROL & CONNECTOR FUNCTIONS section for complete description. When enabled, the power amplifierwill shut down when the PA temp reaches 100 degrees C. If disabled, then the power amplifier will not shutdown dueto HiHi temperature but the HIGH TEMP LED will still flash. Again, for maintaining long life from the power amplifier,it is not recommended to disable High Temperature Shutdown.

Direct Frequency Change The default for this setting is enabled to be able to change the output frequencydirect. If disabled, then attempting to change the output frequency will be ignored by the internal controller. This

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setting is useful for locking out anyone from changing frequencies, or to change frequencies via user programmedchannels.

Channel Frequency Change The default for this setting is enabled to be able to change the output frequency bychannel select. If disabled, then attempting to change the output frequency by selecting channels will be ignored by theinternal controller. This setting is typically disabled if the Direct Frequency Change setting is also disabled. In thatcase, only one frequency can ever be transmitted.

TABLE 1 - Control Switch Settings CommandCONTROL SETTING DIGIT

#7(far leftdigit)

DIGIT#6

DIGIT#5

DIGIT#4

DIGIT#3

DIGIT#2

DIGIT#1

(far rightdigit)

Power Adjust Pot 1 4 0 0 ENB/DIS 0 0HiHi VSWR Foldback 1 2 0 0 ENB/DIS 0 0Reverse Power Calibration 1 1 0 0 ENB/DIS 0 0Forward Power Calibration 1 0 4 0 ENB/DIS 0 0HiHi Temperature Shutdown 1 0 2 0 ENB/DIS 0 0Direct Frequency Change 1 0 0 0 ENB/DIS 2 0Channel Frequency Change 1 0 0 0 ENB/DIS 1 0

Notes:Internal Dip-Switch (S1): Switch 1, 3, and 4 are OFF; Switch2 is ONENB (Enable) = 1, DIS (Disable) = 0Bold selection indicates factory default setting

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THEORY OF OPERATIONRefer to Block Diagram Drawing No. 702-124, 702-117, and appropriate Schematic Diagrams.

CIRCUIT BOARD DESCRIPTIONPRE-AMP/MIXER Board, 800-251A

Each of the four microphone inputs is fed to a low-noise differential op-amp (half of an NE-5532). Critical resistorsin the input circuits are low-noise, precision, temperature stable types to obtain maximum performance from the pre-amps. Monolithic chip capacitors are used to filter RF voltages that may be present at the microphone inputs. The fourop-amp outputs are fed to gain pots then resistively mixed and routed to the COMPRESSOR BOARD.

COMPRESSOR Board, 800-166A (SRPT30/40A-xxx: uses 800-166A40A;SRPT30/40A-450T: uses 800-166A40ATSL)

Several functions are performed on this board. Integrated Circuit IC-1 serves as a (a) pre-amp (not used on theSRPT-30/40A), (b) pre-emphasis amplifier, (c) voltage-controlled attenuator, and (d) regulator /ripple rejection. Pre-emphasized audio out of IC-1B is also fed to D2 - D3 which form an adjustable series peak-limiting circuit. This circuitis adjusted to limit only audio peaks which get past the compressor. The limiter circuit feeds a low-pass filter (L1, C23,and R46) which reduces the audio bandwidth to that specified for the operating channel of the transmitter. To this ismixed the output of the tone encoder, IC-2A, which is a low-distortion Wien bridge oscillator. This composite signal isthen fed to the Modulation port (on P2) of the Transmitter Synthesizer Board, 800-375AT. This audio signal is also fedto IC-2B which amplifies it to a level suitable for a 600 ohm headphone monitor. IC-2C is a DC amplifier the input ofwhich is connected to the AGC (automatic gain control) circuit and the output of which drives the audio compressionmeter.

14.5 VOLT STEP-UP REGULATOR Board, 800-392AThe 800-392A is a DC/DC converter that powers the synthesizer, audio, and mixer boards. It allows the user to

apply an external input voltage (through the 12-15 VDC accessory input pins) as low as 7 VDC and still maintain 14.5volts to the synthesizer and 10.0 volts to the audio and mixer boards. Therefore, the synthesizer will stay locked duringmost power surges and excessive voltage drops. The 800-392A also suppresses any external (or internal) voltage noisesuch as an alternator from a running vehicle. As a result, the SRPT-30/40A still maintains a high signal-to-noise.

TRANSMITTER SYNTHESIZER Board, 800-375ATThe fundamental purpose of this board is to accomplish two things: (1) Generate the final output frequency and (2)

FM modulate the mixed audio. The circuitry to achieve this consists of a Phase-Locked Loop (PLL), which includes aFrequency Synthesizer IC, Voltage-Controlled Oscillator, a pre-scaler, a reference frequency oscillator, and a low-frequency loop filter. The Frequency Synthesizer IC is a programmable device for setting internal counters for allowingthe reference frequency oscillator to be a perfect multiple of the final output frequency. The reference frequencyoscillator is a 12.8 MHz TCXO. The low-frequency loop filter is a one-Hertz active type. The 64/128 pre-scaler is usedto help aid in the multiplying.

The audio output from the 800-166 COMPRESSOR board is fed into the TRANSMITTER SYNTHESIZERs VCOwhich FM modulates the signal at the final output frequency. This modulated RF output signal is then sent to the 800-388A Two-Stage RF PA board for final amplification.

Included on the TRANSMITTER SYNTHESIZER board is a high-speed microcontroller. This controller decodesand acts on commands sent from the Front Panel Control & Meter board (800-378A). These commands include newfrequency change (direct or channel select), control switch settings, calibration, etc. The controller also monitors andregulates forward power, monitors VSWR and PA temperature, performs auto foldback of power due to high VSWRand then recovers when VSWR lowers, and performs auto shutdown of power due to very high temp. It has internalEEPROM for storing important information such as frequency channels and historical info. The controller also detectssynthesizer lock and unlock as well as enabling a fastlock feature for far frequency changes.

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FRONT PANEL CONTROL & METER Board, 800-389A (800-382A some models) SRPT-30 only

This board does the following:- Sends F1/F2 state to TRANSMITTER SYNTHESIZER,- Displays LED alarm information received from the TRANSMITTER SYNTHESIZER,- Receives and decodes digital data from TRANSMITTER SYNTHESIZER for forward and reverse power

readings and converts to analog signals,- Directs POWER ADJUST analog signal to TRANSMITTER SYNTHESIZER,- Multiplexes all analog metering signals via METER SELECT knob for independently monitoring on METER,- Sends state of the TRANSMIT/STANDBY switch.

FRONT PANEL CONTROL & METER Board, 800-385A (800-378A some models) SRPT-40A only

This board does the following:- Collects and sends commands from the front panel pushwheel switches to the on-board microcontroller of the

TRANSMITTER SYNTHESIZER board,- Displays LED alarm information received from the TRANSMITTER SYNTHESIZER,- Receives and decodes digital data from TRANSMITTER SYNTHESIZER for forward and reverse power

readings and converts to analog signals,- Directs POWER ADJUST analog signal to TRANSMITTER SYNTHESIZER,- Multiplexes all analog metering signals via METER SELECT knob for independently monitoring on METER,- Sends state of the TRANSMIT/STANDBY switch.

TWO-STAGE RF POWER AMPLIFIER Board, 800-388A (800-373A some models)The RF output signal (50 mW max) from the TRANSMITTER SYNTHESIZER is fed into this TWO-STAGE RF

POWER AMPLIFIER board. The RF goes through two stages of RF amplification. The first stage (U2) is a 1-Watt(max) pre-driver. It has an input and output transformer (T1 and T2) for achieving optimum 50 Ohm matching betweenthe stages. The output of T2 is fed into the final PA module (U3) for an output of up to 60 Watts max. This PA moduleusually has a lower RF output for SRPT-30s. The signal is then low-passed filtered through FL1 and then fed through adirectional coupler for monitoring forward and reflected power. An Automatic Power Control (APC) circuit residing onthe TRANSMITTER SYNTHESIZER board stabilizes and maintains an accurate output power level by comparing it toa reference power level which is set by the user via the front panel POWER ADJUST pot. The APC circuit samples theforward power via the coupled forward power on PA board.

This board also provides regulated B+ for powering the PA and the rest of the chassis when using 15-30 Voltsexternal supply. Finally, there also exist circuitry for regulating the fan, measuring PA temperature, and monitoring PAcurrent.

SWITCHING POWER SUPPLY, 800-383A (800-324A some models)The Switching Power Supply accepts input from 110-120 or 220-240 VAC and supplies 15 VDC and up to 10

Amperes to power the SRPT-30/40A. The power supply must be switched to the appropriate 115 or 230 position. This isusually done at the factory.

RPU TRANSMITTER I/O Board, 800-379ARThis board passes and distributes external power supply input via the back-panel ACCESSORY connector. It also

passes and directs the ENCODE, TX REM CNTL, and external audio signals. All signals are LC filtered.

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RF SYSTEM & CONTROLRefer to Block Diagram Drawing 702-117. The fundamental RF generation of the SRPT-30/40A takes place on the

TRANSMITTER SYNTHESIZER board in a circuit known as a Phased-Locked Loop (PLL). The final outputfrequency (Fout) is generated by the Voltage Controlled Oscillator (VCO). Fout is determined by the ReferenceFrequency (Fr) and N by the relation: Fout = Fr x N.

N is made up by the internal n and a counters of the Frequency Synthesizer IC and by P, the divide-by-128prescaler. The value N is equal to: N=n x P + a. We can now write Fout in the form: Fout = Fr x (n x P + a).

Therefore, with P as a constant value of 128, the n and a counters can be programmed in such a way that the outputfrequency Fout will always be an integer multiple of the Reference Frequency, Fr. The a-counter will always be anumber from 0 to 128, and the n-counter will be a number from 1 to 1023.

The Reference Frequency, Fr, is generated by the 12.8 MHz TCXO (Temperature Controlled Crystal Oscillator)and the internal R-counter of the Frequency Synthesizer IC. This relation is simply: Fr = Fosc / R, where Fosc = 12.8MHz and R is the programmable R-counter.

The desired output frequency and the Reference Frequency information is sent from the operator via the front panelto the microcontroller. The microcontroller will set the n and a-counters to yield the requested output frequency, and willset the R-counter to yield the requested Reference Frequency. The Reference Frequency is rarely changed, so typically,Fref is treated as a constant and only the output frequency is changed.

The output frequency is modulated by the injected audio at the input of the VCO. The amount of modulation isdetermined by the Modulation setting. The VCO will alter the output frequency in deviation and rate corresponding tothe amplitude and rate (frequency) of the input voltage signal (audio). This is commonly known as frequency modulation(FM). Since the loop filter has a low frequency response (1 Hz), the PLL will not track the modulated signal and as aresult, only the VCO output will change.

The RF power and power control circuit is shared by the TRANSMITTER SYNTHESIZER and the TWO-STAGERF POWER AMPLIFIER. The output of the VCO is sent to a controlled amplifier and is then sent to the TWO-STAGERF POWER AMPLIFIER for final amplification. To maintain a steady and constant RF output (over temperature andvoltage changes), a sample of the RF output power (Forward coupling) is sent to the Automatic Power Control (APC)circuit and compared to a reference output power setting. Any delta changes are instantly compensated for in the APCcircuit and an adjustment is made in the controlled amplifier. A MAX POWER setting can be user adjusted to limit thefinal RF output power.

The low-pass filter (LPF) following the final amplifier will filter out all spurious harmonics to a level lower than 60 dB. The Reverse coupling samples any return power and is sent to the microcontroller. Since the Forward coupling isalso sent to the microcontroller, the VSWR can be determined. The microcontroller will foldback the output power ifthe VSWR exceeds a value of 4. Finally, all front panel alarms and indicators are sent from the microcontroller.

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RECOMMENDED TESTEQUIPMENT

Distortion Analyzer Krohn-Hite Model 6801Oscillator Krohn-Hite Model 4500

Attenuator Set Hewlett-Packard Model 3500Frequency Counter Hewlett-Packard Model 5383A

(option 001)Digital Multimeter Beckman Model 3030Analog Multimeter Triplett Model 630

RF Attenuator adjustable 0-110 dBRF Signal Generator Marconi Model 2022C

Spectrum Analyzer Hewlett-Packard Model 8558BWattmeter (50 ohms impedance) Bird Model 43

5 or 50 watt element 100-250 MHz or 400-1000 MHz, BirdAutomatic Modulation Meter Wavetek Model 4101

50 watt RF Load Microwave Associates Model 44003Stereo Monitor Belar Model FMS-2

Stereo Generator Aphex Model AX400Oscilloscope Tektronix Model 2215

TOOLS FOR ALIGNMENTTuning Tool GC 9300Tuning Tool GC 9440Tuning Tool Spectrol 8T000Tuning Tool Sprague-GoodmanScrewdriver Xcelite R184, 1/8 x 4

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SRPT-30/40A TRANSMITTERFACTORY TEST REPORT

Customer: ________________________ Address: _______________________________________

Serial No.: __________ _______________________________________

____Set internal switching power supply = 13.0 Volts____Program synthesizer____Frequency measurement, adjust, and changing____Forward power calibration and metering____Reverse power calibration and metering____Current metering calibration____Verify B+ metering____Audio board limiter set____Audio compressor meter set to 0 VU____Signal to noise within specifications____Frequency response within specifications____Distortion within specifications____Set deviation to _____kHz corresponding to 100% modulation____Set encode frequency to 27 Hz____Set encode frequency deviation to 600 Hz____Test 12-15 VDC external supply and low-voltage dropout____Calibrate internal regulator and test 15-30 VDC external supply____Test accessory functions

24-Hour Burn-in: Start: Date_________ Time_________Stop: Date_________ Time_________

____Fine tune frequency adjust at ________MHz____Max power adjust to ______Watts

Customer Specific Settings (if different from standard):Encode deviation________ Audio response________ Max power________Channel settings (SRPT-40A only - upon request):CH0:________MHz CH1:________MHz CH2:________MHz CH3:________MHzCH4:________MHz CH5:________MHz CH6:________MHz CH7:________MHzCH8:________MHz CH9:________MHz____Frequency change disabled (SRPT-40A only)____Channel change disabled (SRPT-40A only)

DATE:_____________ SIGNATURE:__________________________________

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CALIBRATION ANDADJUSTMENTSRefer to Location of Adjustments Drawing No. 702-122 and appropriate schematicdiagrams for each module.

This equipment was thoroughly tested and inspected at the factory prior to shipment. The actualequipment performance was recorded on the SRPT-30/40A TRANSMITTER FACTORY TESTREPORT. Adjustments should rarely be necessary in the field and should be attempted only byhighly trained technicians familiar with this type of equipment. Laboratory grade test equipment isrequired and is listed under TEST EQUIPMENT AND TOOLS. For location of adjustments and testpoints in the SRPT-30/40A Transmitter refer to Adjustment Location Diagram, 702-122.

NOTE

FOR ALL ADJUSTMENTS, REMOVE THE TOP COVER FROM THE SRPT-30/40A CHASSIS.

REPLACE THE COVER WHEN THE ADJUSTMENT PROCEDURE IS COMPLETE.

AC Line Input Selection - 110-120 VAC or 220-240 VAC

WARNING

ON FIRST TIME USAGE, WE RECOMMEND THAT THE OPERATOR VERIFIES THAT THE ACINPUT SELECTOR SWITCH IS IN THE POSITION THAT CORRESPONDS TO YOUR AC INPUT

REQUIREMENTS.

1. Remove AC line voltage from SRPT-30/40A.2. Remove the 800-166A COMPRESSOR AUDIO board.3. View the side of the 800-383A Switching Power Supply as shown. For 110-120 VAC applications, the switch

should read 115 and positioned toward the front of the unit. For 220-240 VAC applications, the switchshould read 230 and positioned toward the back of the unit.

4. If the switch position is not in your required position, take a small flat-head screwdriver and switch the ACINPUT switch to the required position.

5. Replace the 800-166A COMPRESSOR AUDIO board.

Switching Power Supply Voltage AdjustmentThe input to the switching power supply can be from 110-120 or 220-240 VAC, 50/60 Hz. The DC B+ output,

measured off of one of the red wires of the switching supply, can be slightly adjusted at B+ ADJUST. The recommendedB+ reading should be 13.0 volts.

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B+ Adjustment When Using 15-30VDC External Supply

CAUTION

THIS ADJUSTMENT HAS BEEN SET AT THE FACTORY AND SHOULD NOT REQUIRE ANYFURTHER ADJUSTMENTS.

1. Remove AC line voltage from SRPT-30/40A.2. Connect up external supply to the 15-30VDC pins of the AUXILLARY connector (see the ACCESSORY Input

Connector paragraph in the CONTROL & CONNECTOR FUNCTIONS section).3. Switch the AC LINE front panel switch to the OFF position.4. Turn on external supply and adjust to approximately 18 VDC.5. Using a VOLT METER, with negative lead connected to ground (chassis), connect the positive lead to one of the

red wires connected to the 800-379AR I/O board.6. On the TWO-STAGE RF POWER AMPLIFIER board adjust EXTERNAL B+ ADJUST (pot R5) in the direction

required to achieve a B+ reading of 13.0 to 13.5 Volts. This voltage should be adjusted with theTRANSMIT/STANDBY switch in STANDBY position.

WARNING

IF THE 15-30 VOLT SUPPLY IS LESS THAN 16 VOLTS, THE EXTERNAL B+ ADJUST SHOULD BESET TO 12 VOLTS.

THIS MAY LIMIT THE MAXIMUM OUTPUT POWER.

Frequency MeasurementThe RF output frequency of this transmitter should be measured as often as necessary to insure on-frequency

operation and to comply with regulations. Monitor the RF output with a frequency counter via an RF coupler or Wattmeter.

WARNING

NEVER CONNECT THE FREQUENCY COUNTER DIRECTLY TO THE RF OUTPUT CONNECTOROF THE SRPT-30/40A.

THE FREQUENCY COUNTER SHOULD BE COUPLED OFF OF AN RF COUPLER OR A WATTMETER.

EXCEEDING THE INPUT POWER RATING OF THE FREQUENCY COUNTER COULD DOINTERNAL DAMAGE TO IT.

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Frequency Fine-Tune Adjust

CAUTION

THIS ADJUSTMENT HAS BEEN SET AT THE FACTORY AND SHOULD NOT REQUIRE ANYFURTHER ADJUSTMENTS.

1. Set the SRPT-30/40A on frequency while transmitting.2. Remove the TRANSMITTER SYNTHESIZER cover.3. On the TRANSMITTER SYNTHESIZER board tweak the FINE TUNE FREQ ADJ (U15) while viewing a

frequency counter.4. Re-install the TRANSMITTER SYNTHESIZER cover.

Front Panel Meter Adjust Forward Power

CAUTION

THIS ADJUSTMENT IS ALSO MADE DURING THE FORWARD POWER CALIBRATIONADJUSTMENT.

IT IS NOT RECOMMENDED TO PERFORM THE FORWARD POWER CALIBRATION JUST TOADJUST THE FRONT PANEL METER - FORWARD POWER.

1. With the SRPT-30/40A powered on and transmitting, tweak the front panel POWER ADJUST pot fully clockwisefor maximum power out.

2. Turn the front panel knob to FORWARD POWER.3. On the FRONT PANEL CONTROL & METER board, tweak the FWD PWR pot (R48) to correlate the front panel

METER (using WATTS scale) to the WATT METER connected to the ANTENNA connector.

Front Panel Meter Adjust Reverse Power

WARNING

THIS ADJUSTMENT SHOULD ONLY BE MADE DURING REVERSE POWER CALIBRATION.

Front Panel Meter Adjust PA Current1. With the SRPT-30/40A powered on and transmitting, tweak the front panel POWER ADJUST pot fully clockwise

for maximum power out.2. On the FRONT PANEL CONTROL & METER board measure the voltage across P6 pin 8 and P6 pin 4, with the

positive lead on P6 pin 8.3. Divide this voltage by 0.025. The result is the PA current.4. Turn the METER SELECT knob to PA CURRENT.5. On the FRONT PANEL CONTROL & METER board adjust the PA CURRENT pot (R50) to set the front panel

METER (using the AMPS scale) to equal the calculated current.

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Maximum Power Adjust

CAUTION

THIS ADJUSTMENT IS ALSO MADE DURING THE FORWARD POWER CALIBRATIONADJUSTMENT.

IT IS NOT RECOMMENDED TO PERFORM THE FORWARD POWER CALIBRATION JUST TOADJUST THE MAXIMUM POWER.

1. Remove the cover from the SYNTHESIZER.2. On the SYNTHESIZER tweak the MAX PWR pot (R74) fully counter-clockwise.3. With the SRPT-30/40A powered on and transmitting, tweak the front panel POWER ADJUST pot fully clockwise.4. On the SYNTHESIZER tweak the MAX PWR pot (R74) clockwise to the desired maximum output power, but do

not exceed Maximum RF Output Power as specified under ORDERING INFORMATION for your model.5. Replace the SYNTHESIZER cover.

Encoder Adjustments1. Connect dummy load with sampling attenuator to ANTENNA connector of SRPT-30/40A.2. Connect an accurate standard FM deviation meter and frequency counter to sampling attenuator.3. Place TRANSMIT/STANDBY switch in TRANSMIT position.4. Place ENCODE switch in ON position and adjust encode level pot R33 on COMPRESSOR AUDIO board, 800-

166 for 600 Hz deviation.5. Connect a scope probe to the bottom leg of R32 of the 800-166 COMPRESSOR AUDIO board and connect the

BNC end of the scope probe to a low-frequency counter.6. Adjust R37 on the 800-166 COMPRESSOR AUDIO board so that the frequency counter reads 27.1 Hz.7. Remove scope probe and return ENCODE switch to OFF position.

Audio Adjustments1. With no audio input, switch METER to AUDIO COMPRESSION position and set ZERO VU ADJUST pot (R22)

on COMPRESSOR AUDIO board, 800-166A to read 0 VU on the meter.2. With ENCODE switch OFF, connect a harmonic distortion analyzer to the audio output of the Marti receiver

being used with the SRPT-30/40A.3. Feed a 100 microvolt signal from the transmitter into the receiver RF input via the sampling attenuator.

WARNING

NEVER FEED THE OUTPUT OF THE SRPT-30/40A DIRECTLY INTO A RECEIVER!

THE INPUT STAGE OF THE RECEIVER WILL BE DESTROYED INSTANTLY!

4. Modulate the transmitter with a 2500 Hz tone at 3 dB compression.5. Turn LIMIT LEVEL pot (R26) on the COMPRESSOR AUDIO board, 800-166 to maximum counter-clockwise

position. Note distortion. It should be less than 2%. Slowly turn R26 clockwise until an additional 0.1% distortion isindicated on the distortion meter.

6. With ENCODE switch ON and using a Marti receiver having a subaudible decoder which has been set to 27 Hzby an audio generator of at least 1% accuracy, adjust ENCODE FREQ pot (R37) for maximum indication on theDECODE SIGNAL LEVEL meter of the receiver.

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7. Connect an audio voltmeter to the output terminals of the Marti receiver. Feed a 100 microvolt signal into thereceiver from an RF attenuator/sampler connected to the output of the transmitter.

8. Using an audio signal generator connected to MIC INPUT 4 (HIGH LEVEL) of the transmitter with a level 20 dBbelow compression level at 2500 Hz, sweep the audio over the audio response range for the transmitter modelnumber being aligned. Refer to the SPECIFICATIONS & ORDERING section for correct response fordesignator on your transmitter.

9. At the maximum specified response frequency, adjust the FREQ RESPONSE tuning slug in coil L1 onCOMPRESSOR AUDIO board, 800-166 for maximum level or best response curve.

Modulation Adjustment1. Connect a modulation (or deviation) meter to the output of the SRPT-30/40A.

WARNING

NEVER CONNECT THE MODULATION METER DIRECTLY TO THE RF OUTPUT CONNECTOR OFTHE SRPT-30/40A.

THE MODULATION METER SHOULD BE COUPLED OFF OF AN RF COUPLER OR A WATTMETER.

EXCEEDING THE INPUT POWER RATING OF THE MODULATION METER COULD DOINTERNAL DAMAGE TO IT.

2. Remove the TRANSMITTER SYNTHESIZER cover.3. Inject a tone into the transmitter at maximum audio modulation (in most cases this is 7.5 KHz) at 3 dB compression.4. Adjust pot R63 on the TRANSMITTER SYNTHESIZER while viewing the modulation meter. Turning the pot

clockwise to increase modulation and turn it counter-clockwise to decrease it.

WARNING

INCREASING THE MODULATION WILL INCREASE THE TRANSMITTER BANDWIDTH!

5. Replace the TRANSMITTER SYNTHESIZER cover.

Procedure for Removing Pre-Amp Mixer Board, 800-2511. Remove knobs and hardware from four level control pots on front panel.2. Notice the Neutrik mic. Connector has a small hole near the center in addition to the three pin receptacles. This hole

contains a tiny locking mechanism. Using a small (0.75 wide) flat blade screwdriver, insert tool into hole and turnslowly until screwdriver engages connector lock. Use care!

3. Turn screwdriver counter-clockwise (1/8 turn) until mic. Insert releases.4. After following the above procedure on each input, gently push the black plastic inserts out of the metal shells while

simultaneously pushing the gain adjust pots inward until the board releases from the front panel.5. Remove board from the chassis and service. To re-install board reverse the above procedure. Be careful! The

locking

Manual de servicio SRPT 30 and SRPT 40A RPU Transmitters Manual

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Transcript of Manual de servicio SRPT 30 and SRPT 40A RPU Transmitters Manual